1. Field of the Invention
The application relates generally to methods for forming thin films comprising oxygen by atomic layer deposition using water as a reactant. Such thin films may find use, for example, in integrated circuits.
2. Description of the Related Art
Atomic layer deposition (ALD) is a self-limiting process, whereby alternated pulses of reactants saturate a substrate surface and leave no more than one monolayer of material per cycle. The deposition conditions and reactants are selected to ensure self-saturating reactions, such that an adsorbed layer in one pulse leaves a surface termination that is non-reactive with the gas phase reactants of the same pulse. A subsequent pulse of a different reactant reacts with the previous termination to enable continued deposition. Thus, each cycle of alternated pulses leaves typically less or no more than about one molecular layer of the desired material. The principles of ALD type processes have been presented, for example, by T. Suntola, e.g. in the Handbook of Crystal Growth 3, Thin Films and Epitaxy, Part B: Growth Mechanisms and Dynamics, Chapter 14, Atomic Layer Epitaxy, pp. 601-663, Elsevier Science B.V. 1994, the disclosure of which is incorporated herein by reference. Variations of ALD have been proposed that allow for modulation of the growth rate. However, to provide for high conformality and thickness uniformity, these reactions are still more or less self-saturating.